Silencer or muffler for engine exhausts or the like



G. B. WALKER SILENCER 0R MUFFLER FOR ENGINE EXHAUSTS OR THE LIKE March9, 1954 w 2 Sheets-Sheet 1 Filed July 5, 1951 SILENCER OR MUFFLER'FORENGINE EXHAUSTS OR THE LIKE Filed July 5, 1951 G. B. WA LKER March 9,1954 2 Sheets-Sheet 2 Patented Mar. 9, 1954 UNITED STATES: 2,671,523

sIn-ENcEn on" UFFLEE-F R-ENGINE EXHAUS-TS R THELIKE GeDrge-" Bro'mheawWalker, Fulham, London, England.

Application July 3; 1951, Serial N0.-"234;954

1 Claim. 1

This invention relates to an improved silencer ormumer for engineexhausts: or'the like}. and more par-ticularly to an improvedconstruction-of the silencer or muffier described in the specificationotmy co-pending United States patent applicatioii Serial No. 144,060,filed February 14, 1950? The object of theinvention is to provideanimproved construction of silencer or muffler which will have greaterefficiency in use with lower back pressure and also is more convenientto manufactu-re.

According to the invention, the improved silencer or muffler comprises acasing of progressively increasing diameter from the inlet end, a hollowcore member with closed opposite ends concentrically supported withinthe casing and co-acting with it to form an annular gas expansion spaceof progressively increasing area receiving the gases from the inlet end,and breather ports or openings in the core member to permit the exhaustgases to pass from the gas expansion space into the hollow core member.The core member functions as a gas accumulator to smooth out thepulsating pressures of the engine exhaust, the gas pressure accumulatingin said hollow core member on the high pressure phase and being releasedthrough the breather ports or openings on the low pressure phase.

The silencer or muflier may also be provided with an outer casing andbreather ports or openings may be formed in the casing to communicatewith the interior of said outer casing, said ports or openings allowingthe exhaust gases to also accumulate in the interior of the outer casingin the same manner as in the hollow core member.

The invention is more fully described aided by reference to theaccompanying drawing wherein:

Fig. 1 is a longitudinal sectional view of the improved silencer ormufller according to one embodiment of the invention.

Figs. 2 and 3 are cross-sections taken on lines 22 and 3--3 of Fig. 1.

Fig. 4 is a longitudinal sectional view of the improved silencer ormufiler according to another embodiment of the invention.

Fig. 5 is a cross-section taken on line 5-5 of Fig. 4.

In the construction shown in Figs. 1 to 3, the silencer 0r mufller has acasing l of progressively increasing diameter from the inlet end 2 and ahollow core member 3 concentrically supported within the casing andco-acting with it to form the annular gas expansion space 4 ofprogressive- 1y increasing cross=sectional area";

closed at both ends and is-centrali'z'ed and sup= to the core memberandare'adapted toengagethe' inner wall of the tapering casing with awedge- The rear end of the core member carries a screwed stud l whichpasses through a central hole 8 in the spider 5 and receives a washer 9and clamping unit 10. The nut Ill may have an elongated or streamlinedtail II. The spider is secured by means of bolts l2 between flangesprovided on the rear end of the casing l and a tapered outlet casing l3.

The forward end of the core member is provided with a tapered nose Mwhich divides the gas stream entering the casing through the inlet end 2into an annular stream as it passes to the as expansion space 4.Rearwardly of said nose breather ports or openings I5 are formed in thecore member to allow the exhaust gases to enter the hollow interior ofthe core member from the expansion space 4.

In use, the exhaust gases entering through the inlet end 2 of the casingI pass along the tapered nose M of the core member into the annular gasexpansion space 4 between said core and the easing. As thecross-sectional area of the expansion space progressively increases, theexhaust gases expand in their passage and so become reduced in pressure.

The ports IS in the core member allow the exhaust gases from theexpansion space to enter the hollow core member which thus functions asa gas accumulator to smooth out the pulsating pressures of the exhaust.On the high pressure phase, the gas pressure accumulates in the hollowcore member and is released on the low pressure phase. Thus, when thegases escape from the outlet they are greatly reduced in pressure andsubstantially free from pulsations. Noise is thereby practicallyeliminated.

In the construction shown in Figs. 4 and 5, the casing l is providedwith an outer casing l6 and a plurality of additional breather holes orports I! are formed in the casing to communicate with the interior ofsaid outer casing. These holes permit the exhaust gases to alsoaccumulate in the interior of the casing IS in the same manner as in thehollow core member 3.

Any moisture condensing in the silencer may escape by providing adraining extension I8 on The core member is of' substantially cyunuricarshape the lower opening of the spider 5, said extension communicatingwith openings 19 in the flanges of the casings I and 13, see Figs. 1 and3. The outer casing IS in the embodiment shown in Figs. 4 and 5 may alsohave a draining hole 20 for the same purpose.

The silencer or mufiler as herein described is more convenient tomanufacture than the previous constructions and, as previouslymentioned, will be found to have greater efliciency with lower backpressure.

What I claim is:

A muilier for engine exhausts comprising a frusto-conical casing havingan inlet end and an outlet end being substantially larger than saidinlet end so that said frusto-conical casing has a progressivelyincreasing diameter from said inlet end to said outlet end, asubstantially cylindrical hollow core member having closed oppositeconical end pieces concentrically supported within said frusto-conicalcasing and coacting with the same so as to form an annular gas expansionspace of progressively increasing area receiving the gases from saidinlet end, and breather ports in said cylindrical core member permittingthe exhaust gases to pass from said gas expansion space into saidcylindrical hollow core member, whereby said progressively increasingexpansion space reduces the back pressure of the mufller and saidcylindrical core member operates as a gas accumulator smoothing out thepulsating pressures of the engine exhaust, the gas pressure accumulatingin said cylindrical hollow core member on the high pressure phase andbeing released through said breather ports on the low pressure phase, anouter casing and breather openings in said frusto-conical casing tocommunicate with the interior of said outer casing, said openingsallowing the exhaust gases to also accumulate in the interior of saidouter casing.

GEORGE BROMHEAD WALKER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 965,135 Gibson July 19, 1910 1,597,397 Wilkinson Apr. 24, 19262,108,671 Kato Feb. 15, 1938 FOREIGN PATENTS Number Country Date 336,705Great Britain Oct. 23, 1930 746,798 France June 6, 1933

